২২৩৭১
A cycle costs Tk. 2,500 when it is brand new. At the end of each year it is worth 4/5 th of what it was in the beginning of the year. What is the worth of the cycle when it is 3 years old?
উত্তর
1280
সমাধান
Here 80% = 0.80 = ⅘,
we see that after 3 years,
the cycle is worth:2,500 x 4/5 x 4/5 x 4/5 = 2,500 x 64/125 = 20 x 64 = 1,280 tk
২২৩৭২
In an examination 75% of the students passed in mathematics, 45% passed in general science and 30% passed in both subject. What per cent of the students have failed in both subject?
উত্তর
10
সমাধান
Percentage of pass in total = Percentage of pass in Bangla + Percentage of pass in English - Percentage of pass in both = 75 + 45 - 30 = 90
So, percentage of fail = 100 - 90 = 10
২২৩৭৩
A lent Tk. 4000 to two persons for one year. Some amount was lent at 5% and the rest at 4%. He got Tk. 180 as interest. How much money was lent at 5%?
উত্তর
2000
সমাধান
Interest, I = P n r
Let the amount lent at 5% be M.
Now, M x 1 x 5/100 + (4000 - M) x 1 x 4/100 = 180
or, 5M + 4(4000 - M) = 180 x 100 [multiply both sides by 100]
or, 5M + 16000 - 4M = 18000
or, M = 18000 - 16000 = 2000 TK
২২৩৭৪
By what per cent the use of fuel is to be reduced in order to keep expenditure on it at same level when its price is increased by25%?
উত্তর
20
সমাধান
Reduction % in consumption = (100 + rr×100)%
= (12525×100) = 20%
২২৩৭৫
In an election between two candidates, one got 55% of the total valid votes. 20% of the votes are invalid. If the total votes are 7500, what is the total number of valid votes the other got?
উত্তর
2700
সমাধান
Total number of votes = 7500
Given that 20% of Percentage votes were invalid
= > Valid votes = 80%
Total valid votes = 7500*(80/100)
1st candidate got 55% of the total valid votes.
Hence the 2nd candidate should have got 45% of the total valid votes
= > Valid votes that 2nd candidate got = total valid votes x (45/100)
7500*(80/100)*(45/100) = 2700
২২৩৭৬
The length and breadth of a rectangle are 24 meters and 12 meter respectively. By what percent the area of the rectangle will increase if its length and breadth are increased by 6%?
উত্তর
12.36
সমাধান
New length = 1.06x, new width = 1.06y
So, new area = 1.06*1.06xy
So, Increase in area = 1.06*1.06 - 1 = 0.1236 = 12.36%
২২৩৭৭
A, B and C enter into partnership with investments in the ratio of 5: 7: 8. If, at the end of the year A's share of profit is Tk. 42360, how much is the total profit?
উত্তর
Tk. 169,440
সমাধান
A's profit = 42,360 = 5x
therefore x = 42,360/5 = 8472
total profit = 5x + 7x + 8x = 20x = 20*8472
total profit = 1,69,440 tk.
২২৩৭৮
What amount of money (in TK) wil grow to Tk. 2380 in eight years if the simple rate of interest applied is 5% per annum?
উত্তর
1700
সমাধান
এখানে ১০০ টাকার জন্য,
এক বছরে ৫ টাকা সুদ হলে ৮ বছরে হবে = (৫*৮) = ৪০ টাকা।
এবং সুদ আসল হবে = (১০০ + ৪০) = ১৪০ টাকা
এখন,
সুদআসল ১৪০ টাকা হলে আসল = ১০০ টাকা
২৩৪০ টাকা সুদআসলের জন্য = ১০০*২৩৪০/১৪০ = ১৭০০ টাকা
২২৩৭৯
The length of a rectangle is three times its breadth. Waht is the perimeter of the rectangle (in meters) if its length is 48 meteres?
উত্তর
128
সমাধান
Here,l = 48, b = 16.
So,perimeter = 2*(48 + 16) = 128
২২৩৮০
If a deposit of Tk.750 earns simple interest @ 8% per annum and that of Tk. 1250 earns the same @6% per annum, what is the average rate of interest (in %) earned on the total deposit?
উত্তর
6.75
সমাধান
Interest on 750*.08 = 60 tk
Interest on 1250*.06 = 75 tk
So, total interest = 135 tk
And, total deposit = 2000 tk
Average interest rate = 135/2000 * 100% = 6.75%